This invention relates generally to hose or tube clamps, and more particularly to an easily releasable clamp having medical applications.
Clamps for flexible tubes or hoses are well-known and are widely used throughout medicine and industry. Many of such clamps include an adjustable band which is adapted to be disposed around an associated tube or hose end to clamp the tube or hose end around an associated structure, such as a tubular connector or the like.
Various types of prior art hose or tube clamps include a band equipped with fittings of various kinds including worm drive devices and single ratchet-type dog-tooth devices for contracting the band to tighten it and clamp the band about a hose or tube which it encircles. These types of prior art clamps suffer disadvantages of one sort or another including being difficult or time consuming to apply, being unreliable in service, being insufficiently strong to sustain the pressures to which the hose or tube and the clamp may be subjected in use, being expensive to manufacture or becoming unserviceable after use. Other types of prior art clamps include an integral helical wire in which the clamp uses an over-center toggle link connected to the helical wire.
Another well-known type of hose or tube clamp includes a pair of cooperating interconnectable jaws, each having a plurality of serrations or teeth adapted for interconnecting engagement. Typically, the teeth are angled such that pushing the jaws toward one another is permitted and tightens the clamp, while the angle of the teeth prevents the jaws from being pulled away from one another to loosen the clamp. These clamps using serrated jaws are often very difficult to loosen, because of the angular orientation of the teeth. In one type of device, such as that shown in U.S. Pat. No. 4,306,740, a screwdriver is required to lift a lever for release and this mechanism requires the application of considerable force. In another embodiment, such as that shown in U.S. Pat. Nos. 4,502,186 and 4,663,807, lateral movement of one jaw with respect to another is required for release, thus distorting the clamp. Other clamps require the lifting of a handle for release which results in the application of force to the clamp or to the hose or tube being encircled by the clamp.
Examples of these clamps are found in U.S. Pat. Nos. 5,157,815; 1,579,719; 1,441,154; and 4,511,164.
None of the foregoing prior art clamps is particularly suitable for medical applications in which secure clamping is desired, but in which it may be undesirable to apply a force to the clamp or tube or hose during removal of the clamp. The application of such a force could damage or break the tube or connector which is being clamped if it is either fragile or easily damaged. Moreover, the application of such a force could cause discomfort or injury to the patient.
A nasal trumpet is one application in which a clamp is desired that can be easily applied and removed without the use of a tool and without the application of a force to the portion of the clamp which encircles the tube or hose. A nasal trumpet is a device that acts as a guide into the nasal passage of a patient to allow easier and more comfortable insertion of a transnasal transesophageal echocardiography (TEE) probe. The nasal trumpet includes a tube formed of a soft, elastomeric material which passes through and is bonded to a support structure for the tube. The support structure in turn is firmly attached to the patient""s head. Typically, the distal end of the tube is inserted into the patient""s nasal passage and the proximal end is secured and supported by the support structure. One device used to secure the support structure to the patient""s head is an elastic band which extends around the back of the patient""s head and which is attached to the support structure. The distal 30-40 cm of the transnasal TEE probe is inserted into the proximal end of the tube that extends from the support structure and that protrudes slightly from the patient""s nose.
Presently, there is no suitable clamp available for securing the trumpet to the transnasal TEE probe. Such a clamp should be capable of providing sufficient clamping force to prevent movement of the probe with respect to the nasal trumpet without damaging the insertion tube of the probe. Such a clamp should also be easy to apply and release without causing injury or discomfort to the patient, and should be capable of accommodating variations in size of the trumpet and insertion tube.
The present invention relates to a tube clamp that overcomes the disadvantages of prior art clamps and that meets the needs of a transnasal TEE probe and nasal trumpet assembly. In one aspect, the tube clamp of the present invention includes a band formed in an open-ended band or loop for encircling the tube. One end of the band terminates in a pair of jaws, while the opposite end of the band terminates in a tongue which is structured to extend between the pair of jaws. The tongue contains a set of serrations or angled teeth on its upper surface which are adapted to mesh with facing, confronting serrations or angled teeth disposed on the lower surface of the upper jaw of the other end of the loop.
In a further aspect, the clamp includes an arm extending outwardly away from the encircling band of the clamp. The arm is affixed to the upper jaw and is pivotable about a hinge section. Pivoting of the arm about its hinge raises the upper jaw away from the tongue to disengage the serrations from one another to permit loosening of the clamp.
In another aspect, the serrations are angled such that movement of the tongue into the jaw is permitted, but withdrawal of the tongue from between the jaws is prevented by interlocking of the serrations on the tongue with the serrations on the upper jaw. The tongue preferably has a spring bias that urges it toward the upper jaw.
In another further aspect, the clamp also includes two spaced handles. A leaf spring may also be provided on one of the two handles and the spring engages the top surface of the upper jaw to urge the upper jaw toward the tongue to urge the serrations on the upper jaw into engagement with the serrations on the upper surface of the tongue. This leaf spring is permitted to flex upwardly away from the upper jaw in response to pivoting of the arm about the hinge to raise the upper jaw. Clamping of a tube is accomplished by squeezing the two handles toward one another to urge the tongue between the jaws until the desired clamping force is obtained. If the arm and the other of the two handles are squeezed together, or if the two handles are moved away from one another, the arm is caused to pivot about its hinge to raise the upper jaw away from the tongue to permit loosening of the clamp. Preferably, the clamp is a one-piece clamp formed of a molded polymeric material.
When the above clamp is used with a transnasal TEE probe, the tube of the trumpet is inserted into the nasal passage of the patient. The support for the tube is affixed to the patient""s head using an elastic band or the like. The outer portion of the proximal end of the tube already contains the clamp loosely positioned. The distal end of the tube is inserted down the nasal passage and into the esophagus of the patient. The transnasal TEE probe is then inserted into the proximal end of the tube of the trumpet until it is in the desired position. At that point, the first and second handles of the clamp are squeezed together to urge the tongue between the jaws until the desired clamping force about the probe tube has been achieved. When the examination is complete, the clamp is removed by squeezing together the first handle and the arm to pivot the upper jaw upwardly away from the tongue to disengage the serrations to permit the first and second handles to be pulled apart to loosen the clamp. The foregoing structure permits the clamp to be readily applied and removed without excessive force on the tube or hose being clamped, or on a patient. The clamp need not be cut or distorted for removal, and no tool is required. These features are particularly important for use in conjunction with a nose trumpet.